Safe use of cricoid pressure.
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Anesthesiology↗
Biomedical subjects
R Griffiths
Publications and source records attributed to R Griffiths.
The use of amplified fragment length polymorphism (AFLP) in the isolation of sex-specific markers.
Sex identification is a problem in research and conservation. It can often be solved using a DNA test but this is only an option if a sex-specific marker is available. Such markers can be identified using the amplified fragment length polymorphism (AFLP) technique. This is usually a taxonomic method, as it produces a DNA fingerprint of 50-100 PCR bands. However, if male and female AFLP products are compared, sex-specific markers are confined to the heterogametic sex and can rapidly be identified. Once a marker is found, AFLP can be used to sex organisms directly or the marker can be sequenced and a standard PCR test designed.
Animals↗
Chronic rejection of mouse kidney allografts.
BACKGROUND: Chronic renal allograft rejection is the leading cause of late graft failure. However, its pathogenesis has not been defined. METHODS: To explore the pathogenesis of chronic rejection, we studied a mouse model of kidney transplantation and examined the effects of altering the expression of donor major histocompatibility complex (MHC) antigens on the development of chronic rejection. RESULTS: We found that long-surviving mouse kidney allografts develop pathological abnormalities that resemble chronic rejection in humans. Furthermore, the absence of MHC class I or class II antigens did not prevent the loss of graft function nor alter the pathological characteristics of chronic rejection. Expression of transforming growth factor-beta (TGF-beta), a pleiotropic cytokine suggested to play a role in chronic rejection, was markedly enhanced in control allografts compared with isografts. However, TGF-beta up-regulation was significantly blunted in MHC-deficient grafts. Nonetheless, these differences in TGF-beta expression did not affect the character of chronic rejection, including intrarenal accumulation of collagens. CONCLUSIONS: Reduced expression of either class I or II direct allorecognition pathways is insufficient to prevent the development of chronic rejection, despite a reduction in the levels of TGF-beta expressed in the allograft. This suggests that the severity of chronic rejection is independent of the level of MHC disparity between donor and recipient and the level of TGF-beta expression within the allograft.
Animals↗
Capnography and "major" accident and emergency departments in East Anglia.
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Capnography↗
Calcium influx via L-type voltage-gated channels mediates the delayed, elevated increases in steady-state c-fos mRNA levels in cerebellar granule cells exposed to excitotoxic levels of glutamate.
The altered kinetics of steady-state c-fos mRNA production in cultured cerebellar granule cells under excitotoxic conditions was investigated in neurons subjected to depolarising stimuli, namely, high KCl and L-glutamate (Glu), in which Ca2+ influx occurs by differing routes. Increases in intracellular-free calcium levels ([Ca2+]i) stimulated by nontoxic or toxic levels of Glu were blocked by selective N-methyl-D-aspartate (NMDA) receptor antagonism; were blocked only partially by the L-type channel blocker, nifedipine; and were unaffected by alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)/kainate receptor antagonists. Glu-induced cell death was prevented only by NMDA receptor blockade. Exposure of cells to nontoxic levels of Glu resulted in a transient increase in c-fos mRNA levels, whereas an excitotoxic dose produced a delay in the appearance of c-fos mRNA but a subsequent, progressive, and sustained (>4 hr) increase. An excitotoxic dose of Glu in combination with either nifedipine or selective NMDA receptor antagonists resulted in the normal, transient increase of c-fos mRNA levels. Chronic exposure to 55 mM KCl caused no cytotoxicity, although it resulted in a delayed, elevated increase in c-fos mRNA levels that was unaffected by NMDA receptor blockade but reverted to the normal, transient profile of c-fos mRNA formation when it was coadministered with nifedipine. The KCl-induced increase in [Ca2+]i levels was inhibited dramatically by nifedipine but was unaffected by any of the ionotropic Glu receptor antagonists. The results support the notion that the appearance of a delayed but elevated increase in steady-state c-fos mRNA levels following exposure to excitotoxic doses of Glu is mediated specifically by calcium influx via L-type voltage-gated channels.
Animals↗
Conscious and preconscious processing of food, body weight and shape, and emotion-related words in women with anorexia nervosa.
OBJECTIVE: The present study was conducted to extend prior research on attention toward food and body weight and shape-related stimuli in women with eating disorders. METHOD: A modified Stroop color-naming task was completed by women with anorexia nervosa and by control females subdivided on a measure of dietary restraint. Eating disorder-relevant word categories included words connoting fatness, words connoting thinness, low caloric density food words, high caloric density food words, and neutral, control words. Valence effects were controlled for by including positively and negatively valenced emotion words. Stimuli were presented under both unmasked and masked conditions. RESULTS: Using unmasked stimuli, patients with anorexia nervosa, but not unrestrained or restrained eaters, had delayed color-naming latencies for both thin and fat word categories and, to a lesser extent, for high caloric density food words. No differences were observed with masked stimuli. DISCUSSION: Our findings suggest that both thinness and fatness are especially salient to women with anorexia. The lack of effects for emotion words suggests that these findings do not reflect a valence effect. We found no evidence for preconscious attentional biases in the masked condition.
Adolescent↗
Attentional biases in eating disorders: a visual probe detection procedure.
OBJECTIVE: To investigate attentional biases for body shape and weight-related stimulus words among subjects with anorexia nervosa, bulimia nervosa, and control subjects classified using a measure of dietary restraint. METHODS: A visual probe detection task was used to assess attention toward stimulus words reflecting either a thin or a large physique and positively or negatively valenced emotion words. RESULTS: In comparison to controls, subjects with eating disorders detected target probes more slowly when they appeared in the same location as had stimulus words connoting a thin physique. In addition, there was a trend toward faster detection or target probes that appeared in the same location as had stimulus words connoting a large physique. Neither of these effects were observed among restrained eaters. DISCUSSION: Our results extend prior work suggesting information-processing biases for body shape and weight-related stimuli among persons with eating disorders.
Adult↗
Perceptions of bed rest by anorexic patients.
OBJECTIVE: Few studies have investigated perceptions of operant conditioning programs by anorexic patients. This study examined patients' perceptions of the Bed Rest (BR) component which is employed in some operant conditioning programs. METHODS: A sample of 48 anorexic inpatients was administered a survey to elicit their attitudes towards BR. RESULTS: Results from the survey suggested that most patients perceived BR in a negative way. The main complaint, however, was not punishment or humiliation, as predicted, but isolation and boredom. A number of patients concluded that they wanted more individualization and distraction and less restriction while on BR. DISCUSSION: The findings justify the use of BR within a humane framework in the inpatient treatment of anorexia nervosa, but suggest that patients' perceptions of BR warrant systematic scrutiny.
Adolescent↗
A different tempo of mitochondrial DNA evolution in birds and their parasitic lice.
A phylogeny for the lice (Insecta: Phthiraptera: genus Dennyus) parasitic on swiftlets (Aves: Collocalliinae) was constructed based on mitochondrial cytochrome b DNA sequences. This phylogeny is congruent with previous phenetic analyses of morphometric data for the lice. Comparison with a previously obtained phylogeny for the hosts indicates some degree of cospeciation. These cospeciation events are used to compare relative rates of evolution in the birds and their lice for the same segment of the cytochrome b gene. Cytochrome b is evolving two to three times more rapidly in lice than in birds, and louse cytochrome b is highly divergent compared to that of most other insects. Although generation time has been suggested as an explanation for the disparity in evolutionary rates between lice and their hosts, we suggest that the small effective population sizes of lice coupled with founder events occurring during transmission to new host individuals may be an important factor.
Amino Acid Sequence↗
Gallstones and isoflurane hepatitis.
This report is of a case of a previously fit 65-year-old woman who developed postoperative liver dysfunction following an anaesthetic involving isoflurane. Biliary ultrasound demonstrated gallstones. However, serum antibodies to trifluoroacetylated proteins were detected, suggesting that immune sensitisation to the anaesthetic could have contributed to the impaired liver function.
Aged↗
A DNA test to sex most birds.
Birds are difficult to sex. Nestlings rarely show sex-linked morphology and we estimate that adult females appear identical to males in over 50% of the world's bird species. This problem can hinder both evolutionary studies and human-assisted breeding of birds. DNA-based sex identification provides a solution. We describe a test based on two conserved CHD (chromo-helicase-DNA-binding) genes that are located on the avian sex chromosomes of all birds, with the possible exception of the ratites (ostriches, etc.; Struthioniformes). The CHD-W gene is located on the W chromosome; therefore it is unique to females. The other gene, CHD-Z, is found on the Z chromosome and therefore occurs in both sexes (female, ZW; male, ZZ). The test employs PCR with a single set of primers. It amplifies homologous sections of both genes and incorporates introns whose lengths usually differ. When examined on a gel there is a single CHD-Z band in males but females have a second, distinctive CHD-W band.
Animals↗
Genetic differentiation among local populations of the European hedgehog (Erinaceus europaeus) in mosaic habitats.
Tissue samples from 160 European hedgehogs, Erinaceus europaeus, representing eight small populations from a highly fragmented landscape in Oxfordshire, UK, were screened for polymorphism at six microsatellite loci. Permutation analysis of allelic compositions revealed no evidence for linkage disequilibrium among loci. Genotype proportions within populations and at five loci did not differ from those expected at Hardy-Weinberg equilibrium. However, significant heterozygote deficit and amplification failure of several samples necessitated removal of one locus from the analysis. Mean observed heterozygosity was 0.70. Average RhoST was 0.079 and differed significantly from zero, suggesting restricted gene flow among local populations. Pairwise Nm values and geographical distance were not correlated, indicating that factors other than distance affected dispersal.
Alleles↗
For debate: public health leadership--do we have it? Do we need it?
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Forecasting↗
A CHD1 gene is Z chromosome linked in the chicken Gallus domesticus.
Chromo-helicase-DNA binding 1 (CHD1) is a conserved protein with a putative role in chromatin architecture. Single homologues have been found in mouse, Drosophila and yeast. In birds the situation is different as they possess two homologues. One is known to be W-linked, we show the second, closely related gene is linked to the Z sex chromosome. The basic structure of the Z-linked gene is similar to the homologous genes, however, it does possess an additional, internal 88 amino acid hydrophilic domain, rich in glutamic acid and lysine. Studies on pairs of genes sex-linked in mammals suggests rapid divergence of DNA sequence and function. We suggest the DNA sequences of CHD-W and CHD-Z do not follow this pattern.
Amino Acid Sequence↗
Association of c-fos mRNA expression and excitotoxicity in primary cultures of mouse neocortical and cerebellar neurons.
The effect of excitatory amino acids (EAAs) on c-fos mRNA expression was studied in primary cultures of mouse cerebellar granule cells and in neocortical neurons after 2 and 7 days in vitro (div). In cultured granule cells at 2 and 7 div, and in cortical neurons at 2 div, exposure to low levels (< or = 10 microM) of a variety of EAAs (viz. glutamate [Glu], S-sulpho-L-cysteine [SC], N-methyl-D-aspartate [NMDA], alpha-amino-3-hydroxy-5-methyl-4-isoxazole [AMPA], and kainate [KA]) resulted in a transient increase in the level of c-fos mRNA which peaked at 30 min but returned to a basal level by 120 min. However, exposure of granule cells (7 div) to high levels (250 microM) of Glu, NMDA, KA, SC and of cortical neurons (7 div) to high levels (250 microM) of Glu, NMDA, KA, SC, or AMPA and to low levels (< or = 10 microM) of Glu and AMPA resulted in a delay in c-fos mRNA induction but a subsequent, progressive increase that was sustained for at least 240 min. Furthermore, this effect was accompanied by a dose-related increase in the release of the cytosolic enzyme, lactate dehydrogenase, used as an indicator of excitotoxicity. A ratio (Q240/30) for the steady-state levels of c-fos mRNA after 30 min and 240 min of exposure to EAAs was determined which showed that Q240/30 >2 correlated reproducibly with excitotoxic cell death, whereas a ratio of < or = 1 correlated with a nonexcitotoxic event. In both cell types at 7 div, coadministration of the selective NMDA receptor antagonist, DL(+/-)-2-amino-5-phosphonopentanoic acid (APV) with cytotoxic levels of Glu 1) protected against EAA-induced neurotoxicity and 2) exhibited a transient c-fos mRNA expression (Q240/30 values approximately 1). In contrast, the AMPA/KA receptor antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), provided no protection against excitotoxicity and had no significant effect on the Glu-induced delay in c-fos mRNA expression. These results suggest that the Q240/30 c-fos mRNA ratio may 1) be used as a predictive index for excitotoxic neuronal death, 2) provide information on the identity of the receptor subtype mediating excitotoxicity in different brain cell types, and 3) aid in establishing the role of excitotoxicity during the development of neurons in vitro.
6-Cyano-7-nitroquinoxaline-2,3-dione↗
Thiamine supplementation mood and cognitive functioning.
One hundred and twenty young adult females took either a placebo or 50 mg thiamine, each day for 2 months. Before and after taking the tablets, mood, memory and reaction times were monitored. An improvement in thiamine status was associated with reports of being more clearheaded, composed and energetic. The taking of thiamine had no influence on memory but reaction times were faster following supplementation. These influences took place in subjects whose thiamine status, according to the traditional criterion, was adequate.
Adult↗
Isolation and characterization of six polymorphic microsatellite loci in the European hedgehog Erinaceus europaeus.
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Animals↗
Sulphur-containing amino acids modulate noradrenaline release from hippocampal slices.
The L- and D-enantiomers of the sulphur-containing amino acids (SAAs)-homocysteate, homocysteine sulphinate, cysteate, cysteine sulphinate, and S-sulphocysteine-stimulated [3H] noradrenaline release from rat hippocampal slices in a concentration-dependent manner. The relative potencies of the L-isomers (EC50 values of 1.05-1.96 mM) were of similar order to that of glutamate (1.56 mM), which was 10-fold lower than that of NMDA (0.15 mM), whereas the D-isomers exhibited a wider range of potencies (0.75 to > 5 mM). All stimulatory effects of the SAAs were significantly inhibited by the voltage-sensitive Na+ channel blocker tetrodotoxin (55-71%) and completely blocked by addition of Mg2+ or Co2- to the incubation medium. All SAA-evoked responses were concentration-dependently antagonized by the selective NMDA receptor antagonist D-(-)-2-amino-5-phosphonopentanoic acid (IC50 values of 3.2 - 49.5 microM). 6-Cyano-7-nitroquinoxaline-2,3-dione (CNQX), a non-NMDA receptor antagonist, at 100 microM inhibited the [3H]noradrenaline release induced by glutamate and NMDA (65 and 76%, respectively) and by all SAAs studied (65-85%), whereas 10 microM CNQX only inhibited the effects of S-sulpho-L-cysteine and L- and D-homocysteate (33, 32, and 44%, respectively). However, the more selective AMPA/kainic acid receptor antagonist 6-nitro-7-sulphamoylbenzo (f) quinoxaline-2,3-dione (100 microM), which did not antagonize the [3H]noradrenaline release induced by glutamate and NMDA, reduced only the S-sulpho-L-cysteine-evoked response (25%). Thus, the stimulation of Ca2(+)-dependent [3H]noradrenaline release from hippocampal slices elicited by the majority of the SAAs appears to be mediated by the NMDA receptor.
2-Amino-5-phosphonovalerate↗